Presently, amorphous silicon solar cells are industrially produced in large quantities by various producers. However, there is a limit for their absolute efficiency when converting solar energy into electricity. Solar cells may be deposited as a thin amorphous silicon film (around 300 nm of thickness) on a respective substrate. However, the efficiency of such solar cells is typically below 6%.
A strategy to increase the efficiency is to increase the light path in a thinner silicon film by light scattering at nano-rough interfaces and subsequently light trapping in the silicon layer. WO 2009/116018 discloses a photovoltaic cell in which a transparent conductive layer is structured to include a plurality of transparent conductive protruding regions. The silicon layer and its charge separating junction have a folded structure which follows the contour of the protruding regions. This folded structure increases the optical thickness of the photovoltaic cell compared to a planar arrangement. However, further improvements to the efficiency of solar cells are desirable.